This question doesn't necessarily have apply to travel experiences, but perhaps one worthy of many thoughts and/or suggestions.
More than anything else, family trips to the beach rank at the top of our list of legacy experiences. Without exception, they all enjoy watching past beach-trip videos and photos:
Getting together at Christmas time is probably the next most memorable experience for our children and grandchildren; our 9 grandchildren do not think Christmas is the same if they don't come to our house for Christmas day meal, opening presents together, and family photo ('07 below):
My wife and I have also taken each of our grandchildren on a trip with us to one of their favorite places (below, two of our younger ones in S.Fran.)
There are many other memorable experiences I could list, such as keeping photo books, videos, but just recently my grandchildren gave me a little book, "Grandpa - His Stories, His Words", and I've been working through my early childhood memories and friends, education, work career, hobbies, etc., recording this for them to one day read. I think this will be a treat for all when I'm no longer around. Hopefully, this will help my children (all married and with their own families) and grandchildren to appreciate the value of "family".(photo below) My wife continues to compile favorite cooking recipes - as our mothers did - and will leave these to our children to continue this tradition.
I hardly knew my parents' parents, and what little experiences I had with a few of them, I don't recall having too many memories that have influenced my life; I don't want this for our grandchildren! One of the great blessings of "fearing the Lord and walking in His ways" is "Indeed, may you see your children's children." (Psalm 128:1, 6)
What are some of the legacies you're leaving to your children and grandchildren - or others?